Control Method for Current-Limiting Control Circuit and Electrical System

ABSTRACT

The present disclosure provides a control method for a current-limiting control circuit and an electrical system. The current-limiting control circuit includes a high voltage side connected with a direct-current (DC) bus, a low voltage side connected with a load, and a regulating unit connected with the high voltage side and the low voltage side, the regulating unit including at least one MOS transistor, and the control method includes: detecting current I0 of the current-limiting control circuit; determining whether the current I0 is greater than a preset current I; and determining that the current-limiting control circuit has a short circuit fault, and entering a current limiting control mode to limit a persistent growth of the current, in a case where the current I0 is greater than the preset current I.

CROSS REFERENCE TO RELATED APPLICATIONS

The present disclosure is a United States National Stage ofInternational Application No. PCT/CN2021/105781 filed Jul. 12, 2021, andclaims priority of Chinese Patent Application No. 202011241184.2 filedNov. 9, 2020, the disclosures of which are hereby incorporated byreference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

The disclosure relates to the field of electrical systems, in particularto a control method for a current-limiting control circuit and anelectrical system.

Description of Related Art

When there is a short circuit, a very large current will be generated inthe circuit, which may burn out an equipment and lines, or even cause afire, leading to large losses. In addition, the entire circuit needs tobe powered off for maintenance and cannot be used normally. In relevanttechnologies, a common scheme is to add an over-current circuit breakeror fuse (protective tube) in the circuit. When the current value exceedsa threshold, the over-current circuit breaker will trip or the fuse(protective tube) will be blown.

SUMMARY OF THE INVENTION

The present disclosure provides a control method for a current-limitingcontrol circuit and an electrical system.

According to the first aspect of the present disclosure, a controlmethod for a current-limiting control circuit is provided. Thecurrent-limiting control circuit comprises a high voltage side connectedwith a direct-current (DC) bus, a low voltage side connected with aload, and a regulating unit connected with the high voltage side and thelow voltage side, the regulating unit comprising at least one MOStransistor, wherein the control method comprises: detecting current I₀of the current-limiting control circuit; determining whether the currentI₀ is greater than a preset current I; and determining that thecurrent-limiting control circuit has a short circuit fault, and enteringa current limiting control mode to limit a persistent growth of thecurrent, in a case where the current I₀ is greater than the presetcurrent I.

According to the second aspect of the present disclosure, an electricalsystem is provided, in which the control method of the current-limitingcontrol circuit described above is adopted.

According to a third aspect of the present disclosure, an electricalsystem is provided, comprising a memory and a processor, wherein thememory stores computer programs, which when executed by the processor,cause the processor to implement the steps of the control method of thecurrent-limiting control circuit according to any embodiment above.

According to a further aspect of the present invention, there is alsoprovided a computer-readable storage medium on which computer programinstructions are stored, which when executed by a processor, cause theprocessor to implement the steps of the control method of thecurrent-limiting control circuit according to any embodiment above.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly explain the embodiments of the presentdisclosure or the technical solutions in the prior art, a briefintroduction will be given below for the drawings required to be used inthe description of the embodiments or the prior art. It is obvious that,the drawings illustrated as follows are merely some of the embodimentsof the present disclosure. For a person skilled in the art, he or shemay also acquire other drawings according to such drawings on thepremise that no inventive effort is involved.

FIG. 1 is a structural diagram of an electrical system according to someembodiments of the present disclosure;

FIG. 2 is a structural diagram of a current-limiting control circuitaccording to some embodiments of the present disclosure;

FIG. 3 is a schematic diagram of control curves in various control modesprovided by the disclosure;

FIG. 4 is a schematic block diagram of an electrical system according tosome embodiments of the present disclosure.

DESCRIPTION OF THE INVENTION

In order to make the technical problem, technical solution andbeneficial effects of the present disclosure more clear and explicit,the present disclosure will be further described in detail incombination with the drawings and the embodiments. It should beunderstood that the detailed embodiments that will be described hereinare only used for explaining the present disclosure, but not used forlimiting the present disclosure.

Therefore, a feature indicated in this description will be used todescribe one of the features of an embodiment of this disclosure, ratherthan imply that each embodiment of this disclosure must have thedescribed feature. In addition, it should be noted that many featuresare described this description. Although some features can be combinedto show a possible system design, these features can also be used forother unspecified combinations. Thus, unless otherwise stated, thestated combinations are not intended to be restrictive.

The principle and structure of the present disclosure will be describedin detail below in conjunction with specific embodiments.

The inventors of the present disclosure have found the followingproblems existed in the above-mentioned related art. In a case of acircuit fault, it is not possible to achieve a non-staged protection andto control the current within a certain range.

In view of this, instead of the above related technologies in which afuse is blown, the present disclosure proposes a control method for acurrent-limiting control circuit and an electrical system, which canlimit a continuous increase in current when the circuit fault occurs.Therefore, the circuit can operate without a break when a fault occurs,rather than being unable to operation after protection. Furthermore, itcan take action in time when an equipment fault occurs, thereby ensuringa timely protection and avoiding problems such as disaster expansion,burnout devices, etc.

In some embodiments, as shown in FIG. 2 , the current-limiting controlcircuit of the present disclosure comprises a high voltage side Cinconnected to a DC bus, a low voltage side Co connected with a load, anda regulating unit connected with the high voltage side and the lowvoltage side. The regulating unit comprises at least one MOS transistor,and the current of the circuit can be adjusted by adjusting the MOStransistor.

As shown in FIG. 2 , the regulating unit is composed of four MOStransistors, namely MOS transistor Q1, MOS transistor Q2, MOS transistorQ3, and MOS transistor Q4. Drain electrodes of MOS transistor Q1 and MOStransistor Q3 are connected together, and connected to an outputterminal of the high voltage side Cin. A source electrode of MOStransistor Q1 is connected to a drain electrode of MOS transistor Q2 andan input terminal of the low voltage side Co. A source electrode of MOStransistor Q3 is connected to a drain electrode of MOS transistor Q4 andthe input terminal of the low voltage side Co. Source electrodes of MOStransistor Q2 and MOS transistor Q4 are connected together, andconnected to an input terminal of the high voltage side Cin and anoutput terminal of the low voltage side Co.

The high voltage side Cin is connected to the low voltage side Cothrough the regulating unit. Current out of the high voltage side Cinand current out of the low voltage side Co must pass through theregulating unit to reach the other side. By adjusting the MOStransistors, it is possible to control an amount of current flowing outand into the MOS transistors, and thereby regulating the current.

In some embodiments, the control method of the current-limiting controlcircuit comprises: detecting current I₀ of the current-limiting controlcircuit; determining whether the current I₀ is greater than a presetcurrent I; and if so, determining that the current-limiting controlcircuit has a short circuit fault, and entering a current limitingcontrol mode to limit a persistent growth of the current.

If the current I₀ is less than the preset current I, thecurrent-limiting control circuit works normally is determined and abidirectional conduction mode is entered to achieve a bidirectionalconduction between the low voltage side and the high voltage sidethrough the MOS transistor and a parasitic diode on the MOS transistor.

In some embodiments, the current limiting control mode comprises: aprimary side voltage droop control mode. In a case where it isdetermined that the current-limiting control circuit has the shortcircuit fault, whether there is a voltage across the load is detectedbefore entering the current limiting control mode. If so, the DC bus hasa short circuit fault is determined, and the primary side voltage droopcontrol mode is entered, which is used to adjust current of the highvoltage side.

In some embodiments, the current limiting control mode further comprisesa secondary side voltage droop control mode. In a case where it isdetermined that the current-limiting control circuit has the shortcircuit fault, whether there is a voltage across the load is detectedbefore entering the current limiting control mode; and the load has ashort circuit fault is determined, and the secondary side voltage droopcontrol mode is entered, which is used to adjust current of the lowvoltage side, in a case where there is no voltage across the load.

In some embodiments, the primary side voltage droop control modecomprises: entering a first droop control stage, and adjusting an inputcurrent of the MOS transistor by adjusting a duty cycle of the MOStransistor to reduce a voltage of the high voltage side and keep anoutput power of the high voltage side unchanged.

In this control stage, the current in the current-limiting controlcircuit increases persistently, and the output voltage of the highvoltage side Cin gradually decreases, remaining the output power of thecurrent-limiting control circuit unchanged. The reason why the currentin the current-limiting control circuit increases for a period of timewhen a fault occurs on the high voltage side is that, when thecurrent-limiting control circuit fails, the current in thecurrent-limiting control circuit has not reached a maximum operatingcurrent that the circuit can withstand, and the current can stillincrease to a certain extent.

When the current has increased to a certain value, the circuit may bedamaged if the current further increases. In this case, it is determinedwhether the current I₀ has reached a threshold current I₁, which is themaximum working current that the current-limiting control circuit canwithstand; if so, a first constant current control stage is entered, aPI adjustment is performed by adjusting the duty cycle of the MOStransistor, to keep current of the high voltage side unchanged.

In some embodiments, FIGS. 3A and 3C show curves of the primary sidevoltage droop control mode. A constant voltage control stage is a normalworking stage of the circuit, in which a goal is to ensure that anoutput voltage is constant. When a fault occurs, a droop control stageis entered, in which the current increases persistently, the voltagedecreases, and the power increases. The current no longer increases whenit reaches the threshold current I₁, and a control is switched toconstant current control. In this case, the actual voltage can beadjusted by adjusting the MOS transistor. At that point, the current isunchanged, and the power changes with the voltage.

As shown in FIGS. 3B and 3D, when a circuit fault occurs, if the currentin the circuit has reached the threshold current the droop control stageis not required, and the control will be directly transferred to theconstant current control stage, causing two-segment curves accordingly.

In some embodiments, the secondary side voltage droop control modecomprises: entering a second droop control stage, and adjusting an inputcurrent of the MOS transistor by adjusting a duty cycle of the MOStransistor to reduce a voltage of the low voltage side and keep anoutput power of the low voltage side unchanged.

In this control stage, the current in the current-limiting controlcircuit increases persistently, and the output voltage of the lowvoltage side Co gradually decreases, remaining the output power of thecircuit unchanged. The reason why the current in the current-limitingcontrol circuit increases for a period of time when a fault occurs onthe low voltage side is that, when the current-limiting control circuitfails, the current in the circuit has not reached the maximum operatingcurrent that the circuit can withstand, and the current can stillincrease to a certain extent.

When the current has increased to a certain value, the circuit may bedamaged if the current further increases. In this case, it is determinedwhether the current I₀ has reached a threshold current I₁, which is themaximum working current that the current-limiting control circuit canwithstand; if so, a second constant current control stage is entered, aPI adjustment is performed by adjusting the duty cycle of the MOStransistor, to keep current of the low voltage side unchanged.

Curves of the secondary side voltage droop control mode are identical tothat of the primary side voltage droop control mode, and reference canbe made to the curves for the primary side voltage droop control, whichwill not be repeated here.

It should be noted here that if the high voltage side or the DC busfails, the primary side voltage droop control mode is adopted, and ifthe low voltage side or load fails, the secondary side voltage droopcontrol mode is adopted, because the primary side voltage droop controlmode is used for current regulation on the high voltage side, while thesecondary side voltage droop control mode is used to control the lowvoltage side. When the high voltage side or the DC bus fails, if thesecondary side voltage droop control mode is adopted, a regulation isrequired to be further transferred to the high voltage side. Therefore,if the high voltage side or the DC bus fails, the primary side voltagedroop control mode is adopted. Similarly, if the low voltage side or theload fails, the secondary side voltage droop control mode is adopted.

In some embodiments, the current limiting control method furthercomprises: a constant power control mode. When the current-limitingcontrol circuit needs to ensure that a power of the low voltage side Coof the circuit, that is, a power of the load, remains unchanged, the MOStransistor is adjusted to change current flowing through the load and avoltage across the load, to maintain the power of the load unchanged.Since a relation between power, voltage and current can be representedby P=IU, the current of the load is inversely proportional to thevoltage of the load when the load power is guaranteed to be constant.When the current flowing through the load increases, the voltage acrossthe load will decrease, and when the current flowing through the loaddecreases, the voltage across the load will increase.

In some embodiments, the current limiting control method furthercomprises a maximum power tracking control mode. It is determinedwhether operating parameters of the current-limiting control circuitmeet a maximum power control condition before entering the currentlimiting control mode; if so, the maximum power tracking control mode isentered; and if not, the current limiting control mode is entered.

In some embodiments, the maximum power tracking control mode comprises:detecting an output power of the low voltage side to obtain a firstdetection power P₀, adjusting a duty cycle of the MOS transistor tochange the output power of the low voltage side, and detecting theoutput power the low voltage side again to obtain a second detectionpower P₁, in a case where the current I0 reaches the threshold currentI₁; determining whether the first detection power P₀ is greater than thesecond detection power P₁; if so, adjusting the duty cycle of the MOStransistor to maintain the output power of the low voltage side to thefirst detection power P₀; and if not, adjusting the duty cycle of theMOS transistor to maintain the output power of the low voltage side tothe second detection power P₁.

Furthermore, the constant power control mode is required before themaximum power tracking control mode. When the current-limiting controlcircuit fails, the current in the circuit has not reached the maximumvalue. In the constant power control mode, the power remains unchangedwhile the current increases persistently. Therefore, it is necessary toexecute the constant power control mode for a period of time to make thecurrent reach the threshold current, so as to obtain the maximum power.

The present disclosure further provides an electrical system, in whichthe control method of a current-limiting control circuit described aboveis adopted.

In some embodiments, as shown in FIG. 1 , the electrical systemcomprises a DC bus and at least one load connected to the DC bus, a highvoltage side of the current-limiting control circuit being connected tothe DC bus, and a low voltage side of the current-limiting controlcircuit being connected to the load.

In some embodiments, as shown in FIG. 4 , the electrical systemcomprises a memory 41, a processor 42, a communication interface 43, anda bus 44. The memory 41 is used to store instructions. The processor 42is coupled to the memory 41, and is configured to, based on instructionsstored in the memory 41, execute the control method of acurrent-limiting control circuit provided in any embodiment describedabove.

In some embodiments, the memory 41 comprises a high speed RAM memory, anon-volatile memory and the like. In some embodiments, the memory 41 isalso a memory array. In some embodiments, the memory 41 is alsopartitioned into blocks, which is combined into virtual volumesaccording to a certain rule. In some embodiments, the processor 42 is acentral processing unit (CPU), or is an Application Specific IntegratedCircuit (ASIC) or one or more integrated circuits configured toimplement the control method of a current-limiting control circuitprovided in the present disclosure.

In some embodiments, the present disclosure further provides acomputer-readable storage medium on which computer program instructionsare stored, which when executed by a processor, cause the processor toimplement the steps of the control method of the current-limitingcontrol circuit according to any embodiment described above.

Those skilled in the art should understand that the embodiments of thepresent disclosure may be provided as a method, a system, or a computerprogram product. Therefore, embodiments of the present disclosure cantake the form of an entirely hardware embodiment, an entirely softwareembodiment or an embodiment containing both hardware and softwareelements. Moreover, the present disclosure may take the form of acomputer program product embodied on one or more computer-usablenon-transitory storage media (comprising but not limited to diskstorage, CD-ROM, optical storage device, etc.) having computer-usableprogram code embodied therein.

Compared with related technologies, the present disclosure provides acontrol method for a current-limiting control circuit and an electricalsystem. When the circuit current increases due to a circuit exception orshort circuit fault, the current can be limited within a certain rangewithout being infinitely increased, and normal operation of the systemcan be maintained; when an equipment exception or short circuit occurs,a protection action can be taken in time to prevent problems such asdisaster expansion, burnout devices, etc. caused by a too large currentin the case of untimely protection; As a replacement of fusingprotection in the relevant technologies, after protection according tothe present application, the circuit can continue to operate normally,thereby the technical problem in the relevant technologies that theentire circuit cannot work uninterruptedly after the fuse is blown canbe solved.

The method and system of the present disclosure may be implemented inmany ways. For example, the method and system of the present disclosuremay be implemented by software, hardware, firmware, or any combinationof software, hardware, and firmware. The above sequence of steps of themethod is merely for the purpose of illustration, and the steps of themethod of the present disclosure are not limited to the above-describedspecific order unless otherwise specified. In addition, in someembodiments, the present disclosure may also be implemented as programsrecorded in a recording medium, which comprise machine-readableinstructions for implementing the method according to the presentdisclosure. Thus, the present disclosure also covers a recording mediumstoring programs for executing the method according to the presentdisclosure.

The above is merely preferred embodiments of this disclosure, and is notlimitation to this disclosure. Within spirit and principles of thisdisclosure, any modification, replacement, improvement and etc. shall becontained in the protection scope of this disclosure.

1. A control method for a current-limiting control circuit, thecurrent-limiting control circuit comprising a high voltage sideconnected with a direct-current (DC) bus, a low voltage side connectedwith a load, and a regulating unit connected with the high voltage sideand the low voltage side, the regulating unit comprising at least oneMOS transistor, wherein the control method comprises: detecting currentI₀ of the current-limiting control circuit; determining whether thecurrent I₀ is greater than a preset current I; and determining that thecurrent-limiting control circuit has a short circuit fault, and enteringa current limiting control mode to limit a persistent growth of thecurrent, in a case where the current I₀ is greater than the presetcurrent I.
 2. The control method according to claim 1, furthercomprising: determining that the current-limiting control circuit worksnormally and entering a bidirectional conduction mode to achieve abidirectional conduction between the low voltage side and the highvoltage side through the MOS transistor and a parasitic diode on the MOStransistor, in a case where the current I₀ is less than the presetcurrent I.
 3. The control method according to claim 1, wherein thecurrent limiting control mode comprises a primary side voltage droopcontrol mode used to adjust current of the high voltage side, and thecontrol method comprises: detecting whether there is a voltage acrossthe load before entering the current limiting control mode; anddetermining that the DC bus has a short circuit fault, and entering theprimary side voltage droop control mode, in a case where there is avoltage across the load.
 4. The control method according to claimwherein the current limiting control mode comprises: a secondary sidevoltage droop control mode and the control method comprises: detectingwhether there is a voltage across the load before entering the currentlimiting control mode; and determining that the load has a short circuitfault, and entering the secondary side voltage droop control mode, whichis used to adjust current of the low voltage side, in a case where thereis no voltage across the load.
 5. The control method according to claim3, wherein the primary side voltage droop control mode comprises:entering a first droop control stage, and adjusting an input current ofthe MOS transistor by adjusting a duty cycle of the MOS transistor toreduce a voltage of the high voltage side and keep an output power ofthe high voltage side unchanged; determining whether the current I₀ hasreached a threshold current I₁, wherein the threshold current I₁ is amaximum working current that the current-limiting control circuit canwithstand; and entering a first constant current control stage, andperforming a PI adjustment by adjusting the duty cycle of the MOStransistor, to keep current of the high voltage side unchanged, in acase where the current I₀ has reached a threshold current I₁.
 6. Thecontrol method according to claim 4, wherein the secondary side voltagedroop control mode comprises: entering a second droop control stage, andadjusting an input current of the MOS transistor by adjusting a dutycycle of the MOS transistor to reduce a voltage of the low voltage sideand keep an output power of the low voltage side unchanged; determiningwhether the current I₀ has reached a threshold current I₁, wherein thethreshold current I₁ is a maximum working current that thecurrent-limiting control circuit can withstand; and entering a secondconstant current control stage, and performing a PI adjustment byadjusting the duty cycle of the MOS transistor, to keep current of thelow voltage side unchanged, in a case where the current I₀ has reached athreshold current I₁.
 7. The control method according to claim 1,further comprising: determining whether operating parameters of thecurrent-limiting control circuit meet a maximum power control conditionbefore entering the current limiting control mode; and entering amaximum power tracking control mode in a case where the operatingparameters of the current-limiting control circuit meet the maximumpower control condition, and entering the current limiting control modein a case where the operating parameters of the current-limiting controlcircuit do not meet the maximum power control condition.
 8. The controlmethod according to claim 7, wherein the maximum power tracking controlmode comprises: detecting an output power of the low voltage side toobtain a first detection power P₀, adjusting a duty cycle of the MOStransistor to change the output power of the low voltage side, anddetecting the output power the low voltage side again to obtain a seconddetection power P₁, in a case where the current I0 reaches the thresholdcurrent I₁; determining whether the first detection power P₀ is greaterthan the second detection power P₁; adjusting the duty cycle of the MOStransistor to maintain the output power of the low voltage side to thefirst detection power P₀, in a case where the first detection power P₀is greater than the second detection power P₁, and adjusting the dutycycle of the MOS transistor to maintain the output power of the lowvoltage side to the second detection power P₁, in a case where the firstdetection power P₀ is lower than the second detection power P₁.
 9. Anelectrical system, in which the control method of a current-limitingcontrol circuit according claim 1 is adopted.
 10. The electrical systemaccording to claim 9, comprising the DC bus and at least one loadconnected to the DC bus, wherein the high voltage side of thecurrent-limiting control circuit is connected to the DC bus, and the lowvoltage side of the current-limiting control circuit is connected to theat least one load.
 11. An electrical system, comprising a memory and aprocessor, wherein the memory stores computer programs, which whenexecuted by the processor, cause the processor to: detect current I₀ ofa current-limiting control circuit, wherein the current-limiting controlcircuit comprising a high voltage side connected with a direct current(DC) bus, a low voltage side connected with a load, and a regulatingunit connected with the high voltage side and the low voltage side, thecomprising at least one MOS transistor; determine whether the current I₀is greater than a preset current I; and determine that the currentlimiting control circuit bus a short circuit fault, and enter a currentlimiting control mode to limit a persistent growth of the current, in acase where the current I₀ is greater than the preset current I.
 12. Acomputer-readable storage medium on which computer program instructionsare stored, which when executed by a processor, cause the processor to:direct current I₀ of a current limiting control circuit, wherein thecurrent-limiting control circuit comprising a high voltage sideconnected with a direct-current (DC) bus, a low voltage side connectedwith a load, and a regulating unit connected with the high voltage sideand the low voltage side, the regulating unit comprising at least oneMOS transistor; determine whether the current I₀ is greater than apreset current I; and determine that the current-limiting controlcircuit has a short circuit fault, and enter a current limiting controlmode to limit a persistent growth of the current, in a case where thecurrent I₀ is greater than the preset current I.
 13. The electricalsystem according to claim 11, wherein the memory further stores computerprograms, which when executed by the processor, cause the processor to:determine that the current-limiting control circuit works normally andentering a bidirectional conduction mode to achieve a bidirectionalconduction between the low voltage side and the high voltage sidethrough the MOS transistor and a parasitic diode on the MOS transistor,in a case where the current I₀ is less than the preset current I. 14.The electrical system according to claim 11, wherein the currentlimiting control mode comprises: a primary side voltage droop controlmode used to adjust current of the high voltage side, and the computerprograms when executed by the processor, cause the processor to: detectwhether there is a voltage across the load before entering the currentlimiting control mode; and determine that the DC bus has a short circuitfault, and enter the primary side voltage droop control mode, in a casewhere there is a voltage across the load.
 15. The electrical systemaccording to claim 11, wherein the current limiting control modecomprises: a secondary side voltage droop control mode and the computerprograms when executed by the processor, cause the processor to: detectwhether there is a voltage across the load before entering the currentlimiting control mode; and determine that the load has a short circuitfault, and enter the secondary side voltage droop control mode, which isused to adjust current of the low voltage side, in a case where there isno voltage across the load.
 16. The electrical system according to claim14, wherein the primary side voltage droop control mode comprises:entering a first droop control stage, and adjusting an input current ofthe MOS transistor by adjusting a duty cycle of the MOS transistor toreduce a voltage of the high voltage side and keep an output power ofthe high voltage side unchanged; determining whether the current I₀ hasreached a threshold current I₁, wherein the threshold current I₁ is amaximum working current that the current-limiting control circuit canwithstand; and entering a first constant current control stage, andperforming a PI adjustment by adjusting the duty cycle of the MOStransistor, to keep current of the high voltage side unchanged, in acase where the current I₀ has reached a threshold current I₁.
 17. Theelectrical system according to claim 15, wherein the secondary sidevoltage droop control mode comprises: entering a second droop controlstage, and adjusting an input current of the MOS transistor by adjustinga duty cycle of the MOS transistor to reduce a voltage of the lowvoltage side and keep an output power of the low voltage side unchanged;determining whether the current I₀ has reached a threshold current I₁,wherein the threshold current I₁ is a maximum working current that thecurrent-limiting control circuit can withstand; and entering a secondconstant current control stage, and performing a PI adjustment byadjusting the duty cycle of the MOS transistor, to keep current of thelow voltage side unchanged, in a case where the current I₀ has reached athreshold current I₁.
 18. The electrical system according to claim 11,wherein the memory further stores computer programs, which when executedby the processor, cause the processor to: determine whether operatingparameters of the current-limiting control circuit meet a maximum powercontrol condition before entering the current limiting control mode; andenter a maximum power tracking control mode in a case where theoperating parameters of the current-limiting control circuit meet themaximum power control condition, and enter the current limiting controlmode in a case where the operating parameters of the current-limitingcontrol circuit do not meet the maximum power control condition.
 19. Theelectrical system according to claim 17, wherein the maximum powertracking control mode comprises: detecting an output power of the lowvoltage side to obtain a first detection power P₀, adjusting a dutycycle of the MOS transistor to change the output power of the lowvoltage side, and detecting the output power the low voltage side againto obtain a second detection power P₁, in a case where the current I0reaches the threshold current I₁; determining whether the firstdetection power P₀ is greater than the second detection power P₁;adjusting the duty cycle of the MOS transistor to maintain the outputpower of the low voltage side to the first detection power P₀, in a casewhere the first detection power P₀ is greater than the second detectionpower P₁, and adjusting the duty cycle of the MOS transistor to maintainthe output power of the low voltage side to the second detection powerP₁, in a case where the first detection power P₀ is lower than thesecond detection power P₁.
 20. The computer-readable storage mediumaccording to claim 12, on which computer program instructions arefurther stored, which when executed by a processor, cause the processorto: determine that the current-limiting control circuit works normallyand entering a bidirectional conduction mode to achieve a bidirectionalconduction between the low voltage side and the high voltage sidethrough the MOS transistor and a parasitic diode on the MOS transistor,in a case where the current I₀ is less than the preset current I.